Electric lamp



H. A. DOUGLAS ELECTRIC LAMP April 12, 1932.

-2 Sheets-Sheet Filed Oct. 30, 1929 @ZZ" 0 V g ,2 13/ @2 JazzgZafi April12, 1932. DQUGLAS 1,853,514

ELECTRIC LAMP Filed Oct. 30, 1929 2 Sheets-Sheet 2 @229 6?. JOagZQfiPatented Apr. 12, 1932 UNETED STATES HARRY A. DOUGLAS, OF BRONSON',MICHIGAN ELECTRIC LAMP Application filed October 30, 1929. Serial No.403,613.

My invention relates to lamp assembly structures which employ lampreceiving sockets and holders for the sockets, more particularly forautomobile headlights. The invention is of particular importance wheresuch a headlight is equippedwith a concave reflector which carries theholder whose bore is in register with an opening provided through thereflector. The invention has for its general object the provision ofmeans whereby thelamp may be fixed with respect to said holder and,where the headlight is equipped with a reflector, may be fixed withrespect to the latter element, also. The invention finds particular usein connection with headlights having parabolic reflectors and enablesthefixed relationship of the lamp filament with respect to the parabolicaxis on which the filament is preferably located. A headlight 29 thusconstructed will'direct light in a fixed path with respect to the axisof the reflector, thereby avoiding difficulty now frequently encounteredin the adaptation. of reflecting headlights to automotive vehicles,bodily or or other adjustment of the lamps having frequently beenrequired when the users happen to find that the light is improperlydirected.

The structure of my invention is inclusive of asocket holder, a lampreceiving socket 39 within said holder and smaller in cross section thanthe holder, and means pressing the socket laterally against one'side ofthe holder.

In a headlight employing a concave reflector,

thesocket holder is fixed with respect to the reflector and has its borein register with an opening that is formed through the reflector topermit of the insertion of the base of an incandescent lamp. In aparabolic reflector this opening therethrough is usually provided in thecrown of the reflector and on the re flector axis. In order that theaxis of the socket may be maintained parallel with the axis of theholder, 1 provide spaced apart spacing means intervening between thehold-' er and socket in the place at which the sock et is pressedagainst the holder. These spacing means are desirably in the form ofribs which extend along the holder and socket. The meansfor pressing thesocket laterally against one side of the holder is desirably in the formof a spring or a pair of springs ,integralwith the holder. In thepreferred embodiment of the invention the pressing means exerts pressureinitially against the base of the "inserted lamp, and through this lampbase, against. the lamp socket to press the lamp socket against theholder, whereby all of these elements are maintained in fixed relation.If the holder be associated with a reflector, the position of the lampfilament with respect to the reflector is assured, it being understoodthat the lamp filaments of the incandescent'lamps which are to be usedin thestructures of my invention preferably occupy predetermined uniformpositions with respect to the lamp bases. To further assure the precisepositions of the lamps, I desirably provide V-shaped seats in thebayonet slots that receive the bayonet pins upon the lamps, so that thelamps are brought to a uniform position rotatively. The lamp socket, inthe structure of my invention, is preferably .pre vented from having anylongitudinal adjustment, so that the spacing of the lamp filament fromthe reflector is fixedly determined. This construction obviates thenecessity of a special design for the reflector which has hitherto beenproposed to procure the same lighting effect with the filament indifferent positions along the reflector axis. The invention, however, isnot to be thuslimited.

The invention will be more fully explained in connection with theaccompanying draw Fig. 1; Fig. 5 is a sectional view on line'55 of Fig.4'; Fig. 6 is a sectional view on line 66 of Fig. i; Fig. 7 is aperspective view illustrating component parts of the structure inseparated relation; and Fig. 8 is a sectional elevation taken throughthe axis of the parabolic reflector.

The headlight illustrated includes a housing or back element 1 having abracket 2 on its bottom side by which it may be assembled with theautomotive vehicle or other sup has its forward end passed through acircular opening formed through the crown of the reflector, in theembodiment of the invention shown. The forward end of the holder 9 isformed with flanges 10 and 11 between which 7 the surrounding edgeportion ofthe reflector is clamped, Wherebythe holder and reflector aremaintained coaxial, in the structure illustrated/ The generallycylindrical lamp socket 12 1s held in assembly with and within theholder 9 by the means hereinafter set forth. This socket is preferablyformed with a single bayonet slot or channel 13 for receiving a bayonetpin or projection 14 upon the base 15 of an incandescent lamp. Thisbayonet pin is maintained in a V-shaped retaining seat 13 of the bayonetslot by any suitable means, the V-shaped seat holding the lamp fromrotati've movement. The means illustrated is inclusive of a coiledspring 16 which surrounds a plunger 17 constituting a circuitterminal'and presses forwardly upon the plunger head 18andrearwardlyupon the flange 19 of a metallic guiding sleeve 20. Thisguiding sleeve is mounted upon an insulating disc .21 which is fixedlyassembled with and within the rear end of the socket 12. The plungerhead 18 presses against a contact 22 which is carried by the generallycylindri' movement, whereby the position of the filacal lamp base 15which is made of insulating material. The lamp structure illustrated isa so-called single pole, though the invention is not to be thus limited.Where a single pole structure is employed, the contact 22 is upon theaxis of the lamp base. A stiff leading in wire 24 establishes connectionbetween the contact 22 and one terminal of the filament 25. Anotherstiff leading in wire 26 estab-. lishe-s a connection between the othertermi-" nal of the filament andthe' metallic sheath 27 which surroundsthe insulating portion of the lamp base and, from the point of view ofmy invention, also constitutes a part or enlargement of the lamp base.The body of the reflector, the holder 9, and'the socket 12' aregroundedand when the lamp is in place the sheath 27 is also grounded asit hasconnection with the holder, as will more fully appear.

In carrying out my invention the cross section of the socket 12 issmaller than the bore of the holder 9 and the base ofthe lamp, in-

clusive of its sheath 27 ,is smaller, in cross section, than the bore ofthe socket.

- Spaced apart spacing means intervene be-.

tween the holder 9 and the socket 12. These spacing means are preferablyin the form of ribs 28 which extend along the holder and socket. Eachrib isdesirably integrally formed with one of the elements 9 or 12, bothribs being shown. as being integrally formed with the holder. The ribsare spaced less than 180 degrees apart, preferably 120 degrees apart.The means for pressing the socket laterally against the holder pressesthe socket against these ribs so that the axis of the socket bears afixed relation to the ribs and to the axis of the reflector that carriesthe holder. Pressure is exerted on a diametrical line that passesbetween the ribs. Means for exerting the pressure is desirably in theform of two spring tongues which are integrally formed with the holder.The free or unattached ends of these tongues are inwardly turned to anextent which causes these tongues to be outwardly flexed, when thesocket is inserted, so that the tongues will exert the desired pressureupon the socket. This pressure upon the socket is desirably exertedthroughthe intermediation of the lamp base whose metallic sheath portionis engaged by the tongues, the electrical connection of the sheath withthe grounded elements being also thereby further assured. In order thatthe tongues may have the desired engagement withthe lamp base, thesocket is formed with an opening 30 through which the free ends.

ment on the reflector axis is fixedly predetermined to avoid specialdesign of the reflector that would be necessary if the'filament weremovable along the reflector axis.

Spaced apart spacing means also intervene between the socket 12 and thelamp base. These spacing means are preferably in the form of ribs 31which extend along the socket and lamp base. Each rib is desirablyintegrally formed with one of the elements 12 or 27, both ribs beingshown as being integrally formed with the socket. These ribs are alsospaced less than 180 degrees apart. preferably 120 degrees apart. Thefree ends of the tongues 29 pressing upon the lamp base not only exertpressure in a line that passes between the ribs 28, but also exert pressure in a'line that passes between the ribs 31. the two pairs of ribsbeing substantially in register.

It will be seen that the socket and lamp are,

by means of the device of my invention, in

fixed relation with each other and with the socket holder and thereflector which carries 955'? the socket holder and, through theintermediation of these elements, with the filament 25 so that thisfilament is maintained in a predetermined definite relation to thereflector. Inthe embodiment of the invention illustrated, the filamentis upon the axis of the reflector, which is preferably parabolic. Thelamps which are designed for use in this structure are manufactured withall filaments in the same relative positions to the lamp bases and asthe lamps are in this respect similar and in other respects also, theymay readily be replaced with the assurance that the filament will comeexactly into the right position with respect to the reflector when anylamp is inserted within its socket.

Changes may be made without departing from the invention.

Having thus described my invention, I claim:

1. The combination with a socket holder; of a lamp receiving socketwithin said holder and smaller in cross section than the bore of theholder; an incandescent lamp having its base within said socket, saidlamp base being smaller in cross section than the bore of the socket; abayonet pin on said lamp base; a t -shaped bayonet seat in said socketfor said pin; means pressing said pin against said seat; spaced apartspacing ribs extending longitudinally in the bore of the holder andintervening between said holder and said socket; spaced apart spacingribs extending longitudinally in the bore of the socket and interveningbetween said socket and said lamp base, the ribs on said holder and theribs on said socket being substantially in register; a slot in saidsocket spaced substantially one hundred and twenty degrees from saidribs; and spring tongues struck from said holder transversely thereof,the free ends of said tongues lying in said slot and pressing againstthe lamp base and, through the lamp base, against the socket, the lengthof said slot longitudinally of the socket being substantially equal tothe width of said tongues.

2. The combination with a socket holder; of a lamp receiving socketwithin said holder and smaller in cross section than the bore of saidholder, said socket being adapted to receive a lamp base smaller incross section than the bore of the socket; spaced apart spacing ribsextending longitudinally in the bore of said holder and adapted tocontact with said socket; spaced apart spacing ribs extendinglongitudinally in the bore of said socket and adapted to contact withsaid lamp base; a slot in said socket spaced substantially one hundredand twenty degrees fromsaid ribs; and a spring having its free end lyingin said slot and being adapted to press against the lamp base when it isinserted in the socket,

whereby the lamp base is pressed against the ribs on the socket and thesocket is against the ribs on the holder.

' 3. The combinationwith a concave reflector having anopening'therethrough; of a socket holder fixed with respect to thereflector and having its bore in register with said opening; a lampreceiving socket within said holder and smaller in cross section thanthe bore of the holder; spaced apart spacing members extendinglongitudinally. of the holder and socket and intervening between. theholder and socket in the :place at which the socket is pressed againstthe holder; an incandescent lamp having its filament within thereflector and its base within the aforesaid socket, said lamp base beingsmaller in cross section than the bore of the socket; spaced apartspacing members extending longitudinally of the socket and lamp base andintervening between the socket and lamp base in the place at which thelamp base is pressed against the socket; and means pressing the socketlaterally against one side of the afore-- said holder to position thesocket with respect to the reflector, said means also pressing the lampbase against one side of the socket to position the lamp filament withrespect toboth socket and reflector. i

4. The combination with a concave reflector having an openingtherethrough; of a socket holder fixed with respect to the reflector andhaving its bore in'register with said opening; a lamp receiving socketwithin said holder and smaller in cross section than the bore of theholder; spacing members extending longitudinally of the holder andsocket and intervening between the holder and socket in the place atwhich the socket is pressed against the holder; and means pressing thesocket laterally against one side of the aforesaid holder to positionthe socket with respect to the reflector, said means including anelement pressing against the internal wall of the socket.

5. The combination with a concave reflector having an openingtherethrough; of a socket holder fixed with respect to the reflector andhaving its bore in register with said open-.

ing; a lamp receiving socket within said pressed holder and smaller incross section than the bore of the holder; spacing members extend-. inglongitudinally of the holder and socket and intervening between theholder and socket in the place at which the socket is pressed againstthe holder, said spacing memline passing diametrically between saidspac-' ing members, said means including an element pressing against theinternal wall of the socket.

' 6. The combination with a socket holder; of a lamp receiving socketwithin said holder:

and smaller in cross section than the bore of the holder; spaced apartspacing ribs extendping longitudinally of the holder and socket .ndintervening between the holder and socket in the place at which thesocket is pressed against the holder; and means pressing the socketlaterally against one side of the hold er,'said means including anelement pressing against the internal wall of the socket and said meansalso locking'the socket against longitudinal movement with respect tothe holder.

3; 7 The combination with'a concave reflector having an openingtherethrough; of a socket holder fixed with respect'to the reflector andhaving its bore in register with said opening; a lamp receiving socketwithin said holdgg'er and smaller in cross section than the bore of theholder; spaced apart spacing ribs ex tending longitudinally of theholder and intervening between the holder and socket in the place atwhich the socket is pressed against 5 the holder; an incandescent lamphaving its filament Within the reflector and its base within theaforesaid socket; spaced apart spacing ribs extending longitudinally ofthe socket and intervening between the socket so and lamp base in theplace at which the lamp base is pressed against the socket; and meanspressing the lamp base laterally against the socket and, through thelamp base, laterally H pressing the socket against the holder. 5 InWitness whereof, I hereuntosubscribe my name. a a

- -H ARRY A. DOUGLAS.

